Secondary auth via ext-jwt-signer fails with legacy auth

[CLBRITTON2]

Reproduce:

• Create an ext-jwt-signer and an auth policy with cert primary auth and that signer as required secondary auth
• Create an identity on that policy and enroll it in ZET
• Attempt to complete the browser auth

The identity never finishes authenticating. The browser spins for a minute and then shows "controller did not respond in time"
This looks like the legacy auth side of openziti/ziti-sdk-c#919, which was fixed for OIDC